In a conventional electric compressor of this kind, a motor-driving circuit is disposed on a body casing in which a compression mechanism and a motor are accommodated (e.g., see patent document 1).
FIG. 3 is a sectional view of a conventional scroll compressor described in the patent document 1. In FIG. 3, an inverter 60 which controls an electric motor is mounted on a radially outer upper surface of a casing 7. The inverter 60 comprises a switching element 62. Among constituent elements of the inverter 60, the switching element 62 generates higher heat. The switching element 62 is supported such that the switching element 62 is pasted on an outer peripheral surface of a cylindrical body 63 in a unit housing 70 in which the inverter 60 is accommodated. The cylindrical body 63 corresponds to a refrigerant passage. A sucked refrigerant can absorb heat from the switching element 62 supported by the cylindrical body 63 and cool the switching element 62. Thus, a radiating member is unnecessary unlike the conventional technique.
[Patent Document 1] Japanese Patent Application Laid-open No. 2002-161859.
However, the conventional structure has a problem that the electric compressor integrally provided with the inverter which drives the electric motor has such an outer shape that the unit housing radially projects from the outer peripheral surface of the substantially cylindrical machine body, the outer shape is distort, and the mountability of the electric compressor on a vehicle is inferior.
The inverter can be disposed in the axial direction, but since the discharge member is formed on a shaft end of the inverter on the side of the compression mechanism, in order to cool a heat-generating part of the inverter, it is necessary to interpose a suction chamber for cooling the heat-generating part between the inverter and the discharge chamber, or to provide some type of radiating member, and this increases the compressor in size and weight.
The present invention has been accomplished to solve such a conventional problem, and it is an object of the invention to provide an electric compressor in which even if the electric compressor is integrally provided with a circuit for driving motor, the mountability of the electric compressor on a vehicle is not deteriorated, and the compressor is not increased in size.